I think it is time to clear this up, okay? Before it gets ugly.
In Which Prue is It, Anyway?, a witch named simply "Brianna" is mentioned, an ancestor of the Charmed Ones. Her surname is unstated, and, if one should gloss over the Book of Shadows story, it does not include one on there either. Therefore, her last name is unknown.
However, on the family tree seen in Pardon My Past, I came across the name Brianna. There is none other by that name seen on the tree. She was the daughter of Bartholomew Bowen and was the sister of Laura Anne Bowen and Jeffrey Bowen, if I remember correctly.
This must mean that her surname was Bowen, not Warren, and the page should be moved. I did it myself, clearly stating why, but HalliwellManor reverted my changes and moved the page back, although admitting that the name Warren was never mentioned and speculating that the Brianna on the page was a different individual. He also insinuated that I faked the image.